DEWS Report (2007) is a review of current knowledge on dry eye by 70 international experts of dry eye and subcommittees of DEWS provides details of dry eye including definition and classification, epidemiology, diagnosis and monitoring, and management and therapy. The report is published in “The Ocular Surface (APRIL 2007, VOL 5, NO. 2 pp. 65-204)” (non-patent literature herein incorporated by reference) and can be viewed at a website (www.tearfilm.org).
According to DEWS Report (2007), dry eye is defined as follows (see “The Definition and Classification of Dry Eye Disease” (p 75-92)): “Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.”
Since dry eye is a multifactorial disease as defined above, treatments of dry eye vary depending on its conditions and symptoms. DEWS Report (2007) classifies dry eye severity level into 4 levels (see “Management and Therapy of Dry Eye Disease” (p 163-178) and Table 2 (p 173)) and provides treatment recommendations for each severity level (see “Management and Therapy of Dry Eye Disease” and Table 4) (p 174)).
According to DEWS Report (2007), there are several agents recommended for dry eye severity levels 1 and 2. However, for dry eye severity level 3 or more, particularly for lesion of ocular surface such as cornea and conjunctiva, there is no recommendable agent other than serum. Further, serum should be derived from blood of a patient to be treated (that is, autologous serum) and should be diluted appropriately when administered to eyes.
At present, substantially, there is no effective agent for dry eye of dry eye severity level 3 or more according to DEWS Report (2007). Therefore, it has been required to establish an animal model representing dry eye according to the classification of DEWS Report (2007), in particular dry eye of dry eye severity level 3 or more according to the report, specifically lesion of ocular surface such as cornea and conjunctiva. Also, by using the animal model for drug screening, it has been required to provide a pharmaceutical composition being useful for dry eye of dry eye severity level 3 or more according to DEWS Report (2007), specifically lesion of ocular surface such as cornea and conjunctiva.